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added support for bi-level PNG's (patch #2301; thanks to Costantino Grana)

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This commit is contained in:
Vadim Pisarevsky 2012-09-11 14:05:25 +04:00
parent b3408a9b3a
commit bb93651048
3 changed files with 16 additions and 6 deletions
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1
modules/highgui/include/opencv2/highgui/highgui.hpp
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@ -176,6 +176,7 @@ enum
IMWRITE_JPEG_QUALITY =1,
IMWRITE_PNG_COMPRESSION =16,
IMWRITE_PNG_STRATEGY =17,
IMWRITE_PNG_BILEVEL =18,
IMWRITE_PNG_STRATEGY_DEFAULT =0,
IMWRITE_PNG_STRATEGY_FILTERED =1,
IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY =2,

1
modules/highgui/include/opencv2/highgui/highgui_c.h
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@ -217,6 +217,7 @@ enum
CV_IMWRITE_JPEG_QUALITY =1,
CV_IMWRITE_PNG_COMPRESSION =16,
CV_IMWRITE_PNG_STRATEGY =17,
CV_IMWRITE_PNG_BILEVEL =18,
CV_IMWRITE_PNG_STRATEGY_DEFAULT =0,
CV_IMWRITE_PNG_STRATEGY_FILTERED =1,
CV_IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY =2,

20
modules/highgui/src/grfmt_png.cpp
View File

@ -357,28 +357,33 @@ bool PngEncoder::write( const Mat& img, const vector<int>& params )
png_init_io( png_ptr, f );
}
int compression_level = 0;
int compression_strategy = Z_RLE;
int compression_level = -1; // Invalid value to allow setting 0-9 as valid
int compression_strategy = Z_RLE; // Default strategy
bool isBilevel = false;
for( size_t i = 0; i < params.size(); i += 2 )
{
if( params[i] == CV_IMWRITE_PNG_COMPRESSION )
{
compression_level = params[i+1];
compression_level = MIN(MAX(compression_level, 0), MAX_MEM_LEVEL);
compression_level = MIN(MAX(compression_level, 0), Z_BEST_COMPRESSION);
}
if( params[i] == CV_IMWRITE_PNG_STRATEGY )
{
compression_strategy = params[i+1];
compression_strategy = MIN(MAX(compression_strategy, 0), Z_FIXED);
}
if( params[i] == CV_IMWRITE_PNG_BILEVEL )
{
isBilevel = params[i+1] != 0;
}
}
if( m_buf || f )
{
if( compression_level > 0 )
if( compression_level >= 0 )
{
png_set_compression_mem_level( png_ptr, compression_level );
png_set_compression_level( png_ptr, compression_level );
}
else
{
@ -389,7 +394,7 @@ bool PngEncoder::write( const Mat& img, const vector<int>& params )
}
png_set_compression_strategy(png_ptr, compression_strategy);
png_set_IHDR( png_ptr, info_ptr, width, height, depth == CV_8U ? 8 : 16,
png_set_IHDR( png_ptr, info_ptr, width, height, depth == CV_8U ? isBilevel?1:8 : 16,
channels == 1 ? PNG_COLOR_TYPE_GRAY :
channels == 3 ? PNG_COLOR_TYPE_RGB : PNG_COLOR_TYPE_RGBA,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
@ -397,6 +402,9 @@ bool PngEncoder::write( const Mat& img, const vector<int>& params )
png_write_info( png_ptr, info_ptr );
if (isBilevel)
png_set_packing(png_ptr);
png_set_bgr( png_ptr );
if( !isBigEndian() )
png_set_swap( png_ptr );